Waste fluid that accumulates during an acute treatment, for example blood treatment, is usually collected in one or more waste bags located on a load cell of the machine. Measuring of volume of the waste fluid is a key feature to control fluid balance of the patient and a critical factor that requires monitoring and safety measures. The volume of the waste fluid contained in the waste bag is determined and supervised by the load cell. Waste bags that are filled during therapy are exchanged to empty ones to continue the therapy after a certain maximum filling volume is reached. In this event a user, for example a nurse or a patient, has to disconnect the bag from the machine. To avoid loss of fluid to the environment care has to be taken and usually clamps on both sides of the bag and the machine have to be closed.
To ease the life of the user, to make therapy more comfortable, to enable the user to use high flow rates and to have less disturbance during a running therapy due to a small number of bag changes, sufficient bag volume is required. However, handling of waste bags of large volume, with a weight of, for instance, 20 kg or even more is very inconvenient for the user.
To reduce volume and weight of the waste fluid containers it is known to use several waste fluid containers of smaller volume and therefore reduced weight instead of one waste fluid container. This enables the user to change the waste liquid container not too frequently, but with several containers of smaller volume at one time. As each container is connected to the same effluent line output, it cannot be achieved and guaranteed automatically, that each container is filled with same volume over time. This drawback may result in overloading one of the containers with the risk of destruction of some of them.
To avoid loss of waste fluid out of the system, especially out of the waste fluid container and the machine when disconnected, the use of standard Luer lock-connectors or manual clamps is state of the art. Current standard waste fluid containers usually comprise a fluid inlet tube provided with a clamp for closing the inlet tube and Luer lock-connector for connection with the machine. Additionally, they comprise a drain line also provided with a clamp for draining the container, if required.